glmmPQL and additive random effects?

Douglas Bates · 2003-04-22T15:35:33Z

Steve Buyske writes: > I'm a bit puzzled by how to write out additive random effects in > glmmPQL. In my situation, I have a factorial design on two > (categorical) random factors, A and B. At each combination, I have a > binary response, y, and two binary fixed covariates, C and D. > > > If everything were fixed, I would use > glm(y ~ A + B + C + D, family = binomial) > > My first thought was to use > glmmPQL(y ~ A + B, random = ~ C + D, family = binomial) > b

Douglas Bates

Tue, Apr 22, 2003 8:35 AM

Steve Buyske <buyske at stat.rutgers.edu> writes:

lme and, by extension, glmmPQL do not handle crossed random effects
easily.  

You must create a factor of the same length as y, A, B, C, and D with
a single level

const = factor(rep(1, length(y)))

then use the non-obvious formulation

glmmPQL(y ~ A + B, random = list(const = pdBlocked(pdIdent(~ C - 1), 
  pdIdent(~ D - 1))))

glmmPQL and additive random effects?

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